Hydraulic brake adjuster



March 11, 1952 w. w. BRANNEN 2,588,955

HYDRAULIC BRAKE ADJUSTER Filed May l5, 1947 2O \\`uljg @I "i5 JW/ Z W 1g L l l il 4o 35 33 34 1B v; ZNVENTOR; W. W. BRANNEN ATTORNEY `each. .wheel .of rthe vehicle. adjustment. is., a.. time-consumingv `operation in ferent positions.

'Patented Mar. 11, 1952 STATE-S PATENT DFF ICE AHYDRAULIC BRAKEKADJUS-IER .Wiley W.,B rannen, Statesboro, Ga., assigner of 1 oneflialfto Alfred A. Dorman, Statesboro, Ga.

' Application May-13, 1947, Serial No..747,`859

`XP-his invention .relates to motor .vehic1eshav- Aingsbraking systems, and more particularly to 1 ,theH .maintenance of braking.. systems .in .proper 4adjustment Yfor ,maximum elliciency of operafilon i: The V.invention is directly4 concerned with ...braking .systems` which.. .are hydraulically.. op-

erated,- and are.v actuated by. means. of a foot .pedal for Vcausing Aoperation of .the brakes, .ordinarllyone adjacent each .of the founw-heel sof-the vehicle.

After -operation of. .the vehicleV for a period A.of time and when .the..'brakelinings .have .be-

come worn it has been necessary to. make `an individual` adjustmentv of the. brake. adjacent Consequently, .an

which considerable.. diiiculty Ais frequently. experienced in obtaining .and .maintaining the .properadjustment and equalization of the brakes,

even foriaskilledmechanic. Therefore, in view .'of the fact .that the. brakes are A such 4an im- -portantfpartof `.the vehicle it is .highly desirable -to` provide the most eiiicient brakes-.and keep ..themf perfectly adjusted.`

vIi'..=-is..an.object of .the .present inventionto .simplify the. adjustment of hydraulically op- .erated brakes ofVA motonvehicles, toreduce the 4.time required. and cost of.. such adjustment,` as .-.well as.v to improve the service .and .eiiiciency of f the brakes.

Aa Vfurther. .object .of the.- invention is to pro- A` vide .simple and...inexpensive.` `mechanism.` `by means o1 -whichthe superior results are obtained,

.andito provide. mechanism .-whichcan :be 4Leasily vapplied to brakesmof. automobiles` already. in

use.

Further objects .and ,advantages .will be ap .parent .from the. .following .description l.taken `in conjunction .with theaccompanyingdrawing, where-nf .--Eigure 1is a diagrammaticcview..illustrating aaframfor-chassis and .braking system .oif an automobile .iwithrfthe presentinvention. applied Hthereto i 10 thefinaster `"cylinder 5I 4 .through the i conduits or fio-545) junction withihe. drums I2 of veach Wheelzare of conventional construction,v and are `supplied i with braking iluid through conduits I3from a master cylinder I4, andthe piston in the master Vcylinder is connected to the/brake V.pedallv'so that when the pedal .is-depressed the. brakes will be operated, the pressure Von, eachbrake f being equal. `Withthe conventionalfbrakes:the

hydraulic braking fluid is supplied vdi'rectlyffrom Y rakeV lines I'Sdirectly` tothe brakes in.` connecy tion, with the Wheels .of .the vehicle.

I .The present invention ladds. an auxiliary. cylinder .I'Iffor providing for easyadjustment .ot the position ofthe brake pedal, and .automatic .ad-

J'ustment of. thebrakes. The a.`,u'xiliaryv brake cylinder .II may. be mounted in Vany desired manner .onl theV `chassis of. ,the vehicle "as, for

example, with apertured .lugs I8 :through which suitableclamping bolts Amay be applied.

. VThreaded..in`to.the uvends of the auxiliary cylinder Ilareplugsll andl20, gaskets Zibeing employed for making .tight joints..V Theend 'i plugs I9 .and,20 arels'ubsta'ntially identicalgthe plug Il) being provided with a .port 22 through `which brake huid vis adapted ,tonow mi@ .the

n auxiliary cylinder through aY connection having f a threaded nipple 23 engaging similar, threads o internally. threaded for receiving. by a ,suitable connection .the `tube v,25 Vfrom; the master cylinder. Theplugml is .provided with aportl intowhich is threaded acoupling 2l, which coupling 21 is adapted to couple yor `fasten t0.a tubeZB/forming a` partof vthe brake line, thus the hydraulic brake iluid "can .enter the auxiliary cylinder through the coupling 124; 4andpass outv through `the `couliling 2].

the ,cylinder ,mounted is @press ....sig., 2,.` a longitudinal. .section .through .the

4 auxiliary; `braking .cylinderconstituting .the` es- .sence of:y the 4present invention; .and

-Fig. 3, asimilar. viewwithpthe parts in diffwiihfcentinued reference.. tothe; drawing.. as

Shown .in Figuren 1. ,the vframe chassis. Hl of an automobile is.s`upported:.b

has brakedrumsj .Oflwhith .there-@r fait in number. The brakes Whiohxoperate inconone end of a piston `33.

vided with extremities inthe form of discs34 and35.` oiffa diameter slightlyv smaller than the internal diameter of. the auxiliary brake oylin der I'I. The piston 33 is also provdedyvith an .annularfange `36 yadjacent .the .enlargedlnsed endf! .Between .thflangesgai andfahollowciip-shaped Washer "3l is disposed andvvhich the` adjusting screw Y23 Withinl fills the space between the piston and the internal wall of the cylinder so that pressure on its cup side will form a tight seal between the piston and the cylinder, but this piston packing will permit a slight amount of fluid to iiow in the opposite direction.

Against the end disc 35 of the piston another cup packing 38 is disposed, and is held in such position by means of a second helical spring 39 bearing against the inner surface of the plug 20, but encompassing a stop 40 to limit the movement of the piston toward the plug 20 in the same manner that the disc 3l applies pressure to the spring 32, and limits the movement of the piston toward the plug I 9.

The auxiliary cylinder and associated parts do not interfere with the normal operation of the braking system of the vehicle. The braking fluid will be forced into the auxiliary cylinder through the line 25 and discharged from the auxiliary cylinder into the line 28. In other words, when the foot pedal I6 is depressed the piston of `the master cylinder, which is similar to the piston of the auxiliary cylinder, will increase pressure of the iiuid in the oil line through the auxiliary cylinder. The pressure is transmitted to the oil line by the piston of the auxiliary cylinder, and if the brakes are not worn no exchange of oil will occur between the master cylinder and the system beyond the auxiliary cylinder. Later, however, when the brake linings are worn in order to compensate for such wear the piston in the auxiliary cylinder will be moved axially until itv engages the plug 40 in the discharge end of the auxiliary cylinder, whereupon with the piston unable to move further toward the discharge end of the auxiliary cylinder iiuid from the master cylinder will be forced around the gaskets 31 and 38 into the system until sufficient to compensate for the 4wear on the brake linings. Release of the brake pedal will permit the piston 33 to return to its normal position, and in so doing the gaskets 3'I` and 38 will expand into contact with the inner Wall of the auxiliary cylinder, confining the oil that has bypassed to the side of the gaskets nearest the discharge end of the auxiliary cylinder, and the brake lines eX- tending'therefrom to the several brakes, consequently providing automatic brake adjustment.

Adjustment of the pressure plate or disc 3l by the screw 29 to which it is swivelly connected will vary'the` tension on the springs 32 and 39, and thus determine the position at which the brake pedal takes effect. This adjustment, therefore, makes it possible to adjust the travel of the brake pedal so that it will actuate the brakes with only a slight depression, or any additional degree of depression selected or desired in accordance with the proper adjustment. This adjustment requires n o particular skill, but can be made by an unskilled mechanic or laborer.

From the foregoing it will be readily understood that by addition of the auxiliary brake cylinder of the present invention automatic adjustment of thebrakes is maintained and with a simple adjustment the position of the brake pedal is controlled.

It will also be readily apparent that the invention is relatively simple and inexpensive, and maybe easily applied or removed, and is much to be desired in the braking systems of motor vehicles;

vIt will be obvious to those skilled in the art that various changes maybe made in theinvention without departing from the spirit and scope thereof, and therefore the invention is not limited by that which is shown in the drawing and described in the specification, but only as indicated in the appended claims.

What is claimed is:

1. A combination brake pedal position and brake adjuster for application in a hydraulic braking system of a vehicle, and comprising a cylinder adapted to contain hydraulic brake fluid, and having inlet and exhaust ports by means of which hydraulic force can be received in and imparted from said cylinder, a piston in said cylinder having flanges extending radially from its axis and terminating in spaced relation to the inner cylinder wall, a packing cup adjacent each of said flanges and constructed to seal against the cylinder wall, said packing being constructed and arranged to seal tightly against the cylinder wall upon receipt of pressure on the side of the packing nearest the discharge port, and adapted to oier limited seal .action against the cylinder wall upon the application of pressure on the opposite side of the packing, spring means at opposite end of said piston tending to maintain said piston in a definite position, means for varying the pressure on said spring means for determining. the travel of the brake pedal, and a stop for limiting the endwise movement of the piston toward the discharge port for causing increase in fluid pressure on the opposite side of the packings from such stop to cause the ow of additional fluid around said packings from the' inlet port to the discharge port of the cylinder. Y

2. A combination brake adjuster for application in a hydraulic breaking system of a vehicle, and comprising a cylinder adapted to contain hydraulic brake fluid, and having inlet and ex- Y haust ports by means of which hydraulic force can be received in and imparted from said cylinder, a piston in said cylinder having iianges extending radially from its axis and terminating in spaced relation to the inner cylinder wall, a packing cup adjacent each of said anges and constructed to seal against the cylinder wall, said packing being constructed and arranged to seal tightly against the cylinder Wall upon receipt or"- pressure on the side of the packing nearest the discharge port, and adapted to oier limited sealing action against the cylinder wall upon the application of pressure on the opposite side of the packing, spring means tending to maintain said piston in a definite position, means for varying the pressure on said spring means for determining the travel of the brake pedal, .and a stop for limiting the endwise movement of the piston toward the discharge port.

3. For use in the hydraulic braking system of a vehicle a cylinder having inlet and discharge ports for the brake fluid, a piston movable between said ports, packing cups disposed one adjacent each end of said piston, spring means tending to maintain said piston in a definite poy sition, said packing cups tending to seal upon application of pressure at one side, and to unseal by application of pressure at the opposite side, a stop for limiting the movement of said piston so that pressure on the unsealing side of said packings will cause flow around the packings in the cylinder, and means for adjusting the tension on said spring means thereby varying the position at which the brake pedalwill become operative A,to actuate the brakes. y' l 4. A. hydraulic brake adjuster comprising ,a cylinder having an inlet at one end and an outlet at the other end, a piston mounted for reciprocation within said cylinder, means on said piston permitting fluid to ow from the inlet side `thereof to the outlet side and preventing iluid from ilowing from the outlet side to the inlet side of said piston, spring means extending side thereof to the outlet side and preventing acting against said piston for determining the normal adjusted position of said piston.

7. For use in the hydraulic braking system of a vehicle a cylinder having inlet and discharge ports for the brake iluid, a piston movable between said ports, packing cups disposed one adjacent each end of said piston, spring means engaging each end of said piston and tending to normally dispose the same substantially midway of said cylinder, said packing cups tending to seal upon application of -pressure at one side thereof and to unseal upon application of pressure to the opposite side, a stop for limiting movei ment of the piston in one direction so that pressure on the unsealing side of said packings will cause flow of fluid thereby, a portion of said z spring means tending to return said piston to uid from flowing from the outlet side to the inlet side of said piston, spring means extending said inlet end of said cylinder for adjusting the` position of the inlet end of said other spring for determining the normal adjusted position of said piston.

6. A hydraulic brake adjuster comprising a cylinder having an inlet at one end and an outlet at the other end, a piston mounted for reciprocation within said cylinder, means on said piston permitting fluid to ow from the inlet side thereof to the outlet side and preventing fluid from owing from the outlet side to the inlet side of said piston, spring means within said cylinder for urging said piston away from the outlet end of said cylinder, a stop for limiting the movement of said piston toward the outlet end of said cylinder, and adjusting means re its original position after contacting said stop, and means for adjusting the tension on said spring means thereby varying the position at which the brake pedal will become operative to actuate thebrakes.

WILEY W. BRANNEN.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 697,140 Goldschmidt Apr. 8, 1902 1,786,231 Dick Dec. 23, 1930 2,156,120 La Brie Apr. 25, 1939 2,240,792 Liebreich May 6, 1941 FOREIGN PATENTS Number Country Date 365,069 Great Britain Jan. 6, 1932 374,150 Great Britain June 6, 1932 

